Have you put in a missing mail request online yet?
https://www.usps.com/help/missing-mail.htm
I've done it a couple times in similar situations and the packages were both found/delivered quickly after
That may just be a coincidence but it's still a step that you need do either way.
I would also request to speak to someone who gives you a better answer than "we'll get back to you" at the local post office, whether that be a supervisor or post master.
They should have very clear tracking information as to why it wasn't delivered and where it went after the "non delivery".
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